I am fixing up a TDI90 for my son when he passes his test. One of the repairs was reconditioned turbo from Midland Turbo's. When the turbo arrived back I was very pleased to see that the only original part appeared to be the casings, everything else looks new. Having installed it in the car I now have the following problem. It seems to behave as if the variable vanes are not there. At full throttle at 1600rpm it only gives 1.1bar (my other tdi90 gives 1.6bar) at 2000rpm it only produces 1.6bar (my other tdi90 produces 2.5bar. Over 2000rpm it does produce 2.2bar but this is still down on the 2.4/5 it should be giving.
Checks I have done:
On fitting it was primed with fresh oil. New gaskets, nuts etc.
I've temporarily blanked off the egr to ensure it is not stuck open.
I've disconnected the exhaust downpipe to ensure that a blocked cat is not causing excess back pressure.
I've pressure tested the boost pipes and intercooler in-situ from the turbo to the anti shudder valve.
I've swapped the MAF with my other tdi90 to rule that out.
I've swapped the inlet pressure sensor with my other tdi90 to rule that out.
I've checked the vacuum system and confirmed that the vane actuator rod is fully pulled in at tickover.
It drives and gives no VCDS codes but its just totally gutless below 2100rpm.
Midland turbo have invited me to send the turbo back and they will check it but obviously I will now have to remove it from the car again.
I desperately don't want it to be a duff refurb or more likely maladjusted variable vane mechanism. The only way I can categorically prove or disprove the turbo is at fault is to swap it with a known good turbo from the other tdi90 but that's a lot of bad back knuckle scraping.
Do any of you mechanical geniuses have any other ideas I could try?
Checks I have done:
On fitting it was primed with fresh oil. New gaskets, nuts etc.
I've temporarily blanked off the egr to ensure it is not stuck open.
I've disconnected the exhaust downpipe to ensure that a blocked cat is not causing excess back pressure.
I've pressure tested the boost pipes and intercooler in-situ from the turbo to the anti shudder valve.
I've swapped the MAF with my other tdi90 to rule that out.
I've swapped the inlet pressure sensor with my other tdi90 to rule that out.
I've checked the vacuum system and confirmed that the vane actuator rod is fully pulled in at tickover.
It drives and gives no VCDS codes but its just totally gutless below 2100rpm.
Midland turbo have invited me to send the turbo back and they will check it but obviously I will now have to remove it from the car again.
I desperately don't want it to be a duff refurb or more likely maladjusted variable vane mechanism. The only way I can categorically prove or disprove the turbo is at fault is to swap it with a known good turbo from the other tdi90 but that's a lot of bad back knuckle scraping.
Do any of you mechanical geniuses have any other ideas I could try?